Basal Cells Show Increased Expression of Aromatase and Estrogen Receptor α in Prostate Epithelial Lesions of Male Aging Rats.

Besides androgens, estrogen signaling plays a key role in normal development and pathologies of the prostate. Irreversible synthesis of estrogens from androgens is catalyzed by aromatase. Interestingly, animals lacking aromatase do not develop cancer or prostatitis, whereas those with overexpression of aromatase and, consequently, high estrogen levels develop prostatitis and squamous metaplasia via estrogen receptor 1 (ERα). Even with this evidence, the aromatase expression in the prostate is controversial. Moreover, little is known about the occurrence of age-dependent variation of aromatase and its association with histopathological changes commonly found in advanced age, a knowledge gap that is addressed herein. For this purpose, the immunoexpression of aromatase was evaluated in the prostatic complex of young adult to senile Wistar rats. ERα was also investigated, to extend our understanding of estrogen responsiveness in the prostate. Moderate cytoplasmic immunoreactivity for aromatase was detected in the glandular epithelium. Eventually, some basal cells showed intense staining for aromatase. The expression pattern for aromatase appeared similar in the normal epithelium when young and senile rats were compared; this result was corroborated by Western blotting. Conversely, in senile rats, there was an increase in the frequency of basal cells intensely stained for aromatase, which appeared concentrated in areas of intraepithelial proliferation and prostatitis. These punctual areas also presented increased ERα positivity. Together, these findings suggest a plausible source for hormonal imbalance favoring estrogen production, which, by acting through ERα, may favor the development of prostatic lesions commonly found in advanced age.

Immunolocalization of steroidogenic enzymes in the vaginal mucous of Galea spixii during the estrous cycle.

BACKGROUND: The synthesis of sex steroids is controlled by several enzymes such as17α-hydroxylase cytochrome P450 (P450c17) catalyzing androgen synthesis and aromatase cytochrome P450 (P450arom) catalyzing estrogen synthesis, both of which must complex with the redox partner NADPH-cytochrome P450 oxidoreductase (CPR) for activity. Previous studies have identified expression of steroidogenic enzymes in vaginal tissue, suggesting local sex steroid synthesis. The current studies investigate P450c17, P450aromatase and CPR expression in vaginal mucosa of Galea spixii (Spix cavy) by immuno-histochemical and western immunoblot analyses. METHODS: Stages of estrous cyclicity were monitored by vaginal exfoliative cytology. After euthanasia, vaginal tissues were retrieved, fixed and frozen at diestrus, proestrus, estrus and metestrus. The ovaries and testis were used as positive control tissues for immunohistochemistry. RESULTS: Data from cytological study allowed identification of different estrous cycle phases. Immunohistochemical analysis showed different sites of expression of steroidogenic enzymes along with tissue response throughout different phases of the estrous cycle. However, further studies are needed to characterize the derived hormones synthesized by, and the enzymes activities associated with, vaginal tissues. CONCLUSION: Current results not only support the expression of enzymes involved in sex steroid synthesis in the wall of the vagina, they also indicate that expression changes with the stage of the cycle, both the levels and types of cells exhibiting expression. Thus, changes in proliferation of vaginal epithelial cells and the differentiation of the mucosa may be influenced by local steroid synthesis as well as circulating androgens and estrogens.

Immunohistochemical expression of matrix metalloproteinases in ameloblastomas and pericoronal follicles.

BACKGROUND: Ameloblastoma (AM) is a benign odontogenic neoplasm characterized by local invasiveness and recurrence. We compared the immunohistochemical expression of matrix metalloproteinases in different clinical types of AM as well as in normal odontogenic tissue. METHODS: Thirteen cases of solid AMs, five cases of unicystic AM and eight pericoronal follicles (PF) were selected and subjected to immunohistochemical investigation for matrix metalloproteinase-1, matrix metalloproteinase-2 and matrix metalloproteinase-9 expressions. RESULTS: The expressions of MMP-1 and MMP-2 were very high in the cytoplasm of cells throughout the entire epithelium and in fibroblasts from the adjacent connective tissue. MMP-9 expression was observed in the same location although with weaker staining. The Kruskal-Wallis test showed statistically significant differences in the epithelial expressions of MMP-1 and MMP-2; there was lower expression among solid AMs when compared with unicystic AM and PF. Compared to both types of AM, higher stromal expression of MMP-9 was found in PF. CONCLUSION: MMP-1, MMP-2 and MMP-9 seem to be associated with AM tumour behaviour as well as physiological tissue remodelling within PF.

Calcifying Cystic Odontogenic Tumour: immunohistochemical expression of matrix metalloproteinases, their inhibitors (TIMPs and RECK) and inducer (EMMPRIN).

BACKGROUND: Calcifying cyst odontogenic tumour (CCOT) is a rare benign cystic neoplasm of odontogenic origin. MMPs are responsible for extracellular matrix remodelling and, together their inhibitors and inducer, determinate the level of its turnover in pathological processes, leading to an auspicious microenvironment for tumour development. Thus, our goal was to evaluate matrix metalloproteinases (MMPs-2, -7, -9 and -14), their inhibitors (TIMPs-2, -3, -4 and RECK) and its inductor (EMMPRIN) expression in CCOT. MATERIALS AND METHODS: We used 18 cases of CCOT submitted to immunolocalization of the target proteins and analysed in both neoplastic odontogenic epithelial and stromal compartments. RESULTS: All molecules evaluated were expressed in both compartments in CCOT. In epithelial layer, immunostaining for MMPs, TIMPs, RECK and EMMPRIN was found in basal, suprabasal spindle and stellate cells surrounding ghost cells and ghost cells themselves, except for MMP-9 and TIMP-2 which were only expressed by ghost cells. In stromal compartment, extracellular matrix, mesenchymal (MC) and endothelial cells (EC) were positive for MMP-2, -7, TIMP-3 and -4, while MMP-9, TIMP-2 and RECK were positive only in MC and MMP-14 only in EC. Statistical significance difference was found between both compartments for MMP-9 (P < 0.001), RECK (P = 0.004) and EMMPRIN (P < 0.001), being more expressed in epithelium than in stroma. Positive correlation between both stromal EMMPRIN and RECK expression was found (R = 0.661, P = 0.003). CONCLUSIONS: We concluded that these proteins/enzymes are differentially expressed in both epithelium and stroma of CCOT, suggesting an imbalance between MMPs and their inducer/inhibitors may contribute on the tumour behaviour.

Seasonal variation in estrogen receptor ERα, but not ERß, androgen receptor and aromatase, in the efferent ductules and epididymis of the big fruit-eating bat Artibeus lituratus.

The efferent ductules (ED) are a major target for estrogens, which act via the estrogen receptors ERα (ESR1) and ERß (ESR2). ERα has been found in the ED of all species studied so far. However, in the epididymis (EP), the expression of ERα is controversial, as is data about the occurrence of aromatase in the epithelium lining the excurrent ducts. Therefore, to further investigate this estrogen-responsive system, we used a seasonal breeder, the Neotropical bat, Artibeus lituratus, in which testicular expression of androgen (AR) and estrogen (ER) receptors vary with reproductive phase. The localization of aromatase, ERα, ERß and AR in the ED and EP of A. lituratus was investigated. The results showed that aromatase, AR and ERß were distributed throughout the excurrent ducts and did not vary during the annual reproductive cycle. Conversely, ERα was detected primarily in the ED epithelium, had marked seasonal variation and was increased during regression, especially in the EP epithelium. The results suggest that ERα may be involved in preparing the male genital tract for recrudescence. Together, the data obtained under natural conditions emphasize that specific segments of the excurrent ducts downstream of the testis are the primary targets for estrogen action via ERα, which is similar to previous findings in animals lacking functional ERα.

Localization and hormonal regulation of endometrial matrix metalloproteinase-26 in the rhesus macaque.

BACKGROUND: The current understanding of hormonal regulation of matrix metalloproteinase-26 (MMP-26) in the primate endometrium is incomplete. The goal of this work was to clarify estrogen and progesterone regulation of MMP-26 in the endometrium of ovariectomized, hormone-treated rhesus macaques. METHODS: Ovariectomized rhesus macaques (n= 66) were treated with estradiol (E(2)), E(2) plus progesterone, E(2) followed by progesterone alone or no hormone. Endometrium was collected from the hormone-treated animals during the early, mid- and late proliferative and secretory phases of the artificial menstrual cycle. MMP-26 expression was quantified by real-time PCR, and MMP-26 transcript and protein were localized by in situ hybridization and immunohistochemistry and correlated with estrogen receptor 1 and progesterone receptor (PGR). RESULTS: MMP-26 was localized to glandular epithelium and was undetectable in the endometrial stroma and vasculature. MMP-26 transcript levels were minimal in the hormone-deprived macaques and treatment with E(2) alone did not affect MMP-26 levels. Treatment with progesterone both in the presence and absence of E(2) stimulated MMP-26 expression in the early and mid-secretory phases (P < 0.001). MMP-26 expression preceded decidualization of endometrial stroma. MMP-26 levels then declined to baseline in the late secretory phase (P < 0.01) despite continued E(2) plus progesterone treatment. Loss of detectable MMP-26 expression in the late secretory phase was correlated with late secretory phase loss of glandular epithelial PGR. CONCLUSIONS: Endometrial MMP-26 expression is dependent on the presence of progesterone in the early secretory phase and then gradually becomes refractory to progesterone stimulation in the late secretory phase. In the macaque, MMP-26 is a marker of the pre-decidual, secretory endometrium. During the second half of the late secretory phase, and during decidualization, MMP-26 loses its response to progesterone concurrent with the loss of epithelial PGR. The decline in MMP-26 levels between the mid- and late secretory phases may play a role in the receptive window for embryo implantation.

Comparative analysis of the immunohistochemical expression of collagen IV, MMP-9, and TIMP-2 in odontogenic cysts and tumors.

OBJECTIVE: The aim of this study was to evaluate the immunohistochemical expression of collagen IV, matrix metalloproteinase (MMP) 9 and tissue inhibitor of MMP (TIMP) 2 in dentigerous cysts (DCs), radicular cysts (RCs), keratocystic odontogenic tumors (KOTs), and ameloblastomas. STUDY DESIGN: Twenty cases of DCs, 20 RCs, 20 KOTs, and 20 ameloblastomas were selected and analyzed by immunohistochemistry. RESULTS: Most DCs and RCs showed continuous and >50% staining for collagen IV in the basement membrane of the epithelium, whereas predominantly discontinuous thin and ≤ 50% staining was observed in KOTs and ameloblastomas, with a significant difference in staining percentage (P < .001). MMP-9 was diffusely distributed and localized in both epithelial and mesenchymal cells of all of the lesions analyzed. The staining percentage was higher in the epithelium (P = .058) and mesenchyme (P = .005) of KOTs and ameloblastomas. Moreover, the distribution pattern, location, and percentage of expression of TIMP-2 were similar in the lesions studied, except for ameloblastoma, with a significant difference in staining percentage (P < .001). CONCLUSION: These results demonstrate that the interaction between collagen IV, MMP-9, and TIMP-2 is an important factor for the establishment of differences in the biologic behavior of the odontogenic cysts and tumors studied.

In vitro effect of valepotriates isolated from Valeriana glechomifolia on rat P-type ATPases.

Valepotriates are iridoids found in variable amounts in Valerianaceae and might be among the bioactive compounds which confer anxiolytic properties to the Valeriana species. On the other hand, unspecific cytotoxicity has also been described. Presently, however, no particular molecular target has been defined for these compounds. Here we studied the effect of valtrate, acevaltrate, and 1- ß-acevaltrate isolated from Valeriana glechomifolia on the enzymatic activity of rat P-type ATPases. Valepotriates did not affect rat skeletal muscle sarco/endoplasmic reticulum Ca²âº-ATPase (SERCA) activity at the highest concentration used (100 µM). In contrast, the same concentration inhibited roughly half of the total H⁺/K⁺-ATPase activity from rat gastric epithelium (valtrate 54.6 ± 3.2 %, acevaltrate 60.7 ± 7.3 %, 1- ß-acevaltrate 50.2 ± 3.1 %; mean ± SEM, n = 3-5). Finally, these substances showed the highest inhibitory potency toward Na⁺/K⁺-ATPase, and the inhibition curves obtained provided a similar IC50 (in µM) for rat kidney α1 isoform (valtrate 21.2, acevaltrate 22.8, 1- ß-acevaltrate 24.4) and brain hemispheres α2/ α3 isoforms (valtrate 19.4, acevaltrate 42.3, 1- ß-acevaltrate 38.3). Our results suggest that P-type ATPases are differentially inhibited by valepotriates and that Na⁺/K⁺-ATPase might be one of their molecular targets in vivo.

Structural and biochemical correlates of Na+,K+-ATPase driven ion uptake across the posterior gill epithelium of the true freshwater crab, Dilocarcinus pagei (Brachyura, Trichodactylidae).

To better comprehend the structural and biochemical underpinnings of ion uptake across the gills of true freshwater crabs, we performed an ultrastructural, ultracytochemical and morphometric investigation, and kinetically characterized the Na(+),K(+)-ATPase, in posterior gill lamellae of Dilocarcinus pagei. Ultrastructurally, the lamellar epithelia are markedly asymmetrical: the thick, mushroom-shaped, proximal ionocytes contain elongate mitochondria (41% cell volume) associated with numerous (≈14 µm² membrane per µm³cytoplasm), deep invaginations that house the Na(+),K(+)-ATPase, revealed ultracytochemically. Their apical surface is amplified (7.5 µm² µm⁻²)) by stubby evaginations whose bases adjoin mitochondria below the subcuticular space. The apical membrane of the thin, distal ionocytes shows few evaginations (1.6 µm² µm⁻²), each surrounding a mitochondrion, abundant in the cytoplasm below the subcuticular space; basolateral invaginations and mitochondria are few. Fine basal cytoplasmic bridges project across the hemolymph space, penetrating into the thick ionocytes, suggesting ion movement between the epithelia. Microsomal Na(+),K(+)-ATPase specific activity resembles marine crabs but is ≈5-fold less than in species from fluctuating salinities, and freshwater shrimps, suggesting ion loss compensation by strategies other than Na(+) uptake. Enzyme apparent K(+) affinity attains 14-fold that of marine crabs, emphasizing the relevance of elevated K(+) affinity to the conquest of fresh water. Western blotting and biphasic ouabain inhibition disclose two α-subunit isoforms comprising distinct functional isoenzymes. While enzyme activity is not synergistically stimulated by NH(4) (+) and K(+), each increases affinity for the other, possibly assuring appropriate intracellular K(+) concentrations. These findings reveal specific structural and biochemical adaptations that may have allowed the establishment of the Brachyura in fresh water.

Tracheal cryopreservation: caspase-3 immunoreactivity in tracheal epithelium and in mixed glands

Cryopreservation has an immunomodulating effect on tracheal tissue as a result of class II antigen depletion due to epithelium exfoliation. However, not all epithelium is detached. We evaluated the role of apoptosis in the remaining epithelium of 30 cryopreserved tracheal grafts. Caspase-3 immunoreactivity of tracheal epithelium was studied in canine tracheal segments cryopreserved with F12K medium, with or without subsequent storage in liquid nitrogen at -196°C for 15 days. Loss of structural integrity of tracheal mixed glands was observed in all cryopreserved tracheal segments. Caspase-3 immunoreactivity in tracheal mucosa and in mixed glands was significantly decreased, in contrast to the control group and to cryopreserved tracheal segments in which it remained high, due to the effect of storage in liquid nitrogen (P < 0.05, ANOVA and Tukey test). We conclude that apoptosis can be triggered in epithelial cells during tracheal graft harvesting even prior to cryopreservation, and although the epithelial caspase-3 immunoreactivity is reduced in tracheal cryopreservation, this could be explained by increased cell death. Apoptosis cannot be stopped during tracheal cryopreservation.

Tracheal cryopreservation: caspase-3 immunoreactivity in tracheal epithelium and in mixed glands.

Cryopreservation has an immunomodulating effect on tracheal tissue as a result of class II antigen depletion due to epithelium exfoliation. However, not all epithelium is detached. We evaluated the role of apoptosis in the remaining epithelium of 30 cryopreserved tracheal grafts. Caspase-3 immunoreactivity of tracheal epithelium was studied in canine tracheal segments cryopreserved with F12K medium, with or without subsequent storage in liquid nitrogen at -196 degrees C for 15 days. Loss of structural integrity of tracheal mixed glands was observed in all cryopreserved tracheal segments. Caspase-3 immunoreactivity in tracheal mucosa and in mixed glands was significantly decreased, in contrast to the control group and to cryopreserved tracheal segments in which it remained high, due to the effect of storage in liquid nitrogen (P < 0.05, ANOVA and Tukey test). We conclude that apoptosis can be triggered in epithelial cells during tracheal graft harvesting even prior to cryopreservation, and although the epithelial caspase-3 immunoreactivity is reduced in tracheal cryopreservation, this could be explained by increased cell death. Apoptosis cannot be stopped during tracheal cryopreservation.

Immunohistochemical expression of matrilysins (MMP-7 and MMP-26) in ameloblastomas and adenomatoid odontogenic tumors.

OBJECTIVE: The aim was to evaluate the expression of matrix metalloproteinases (MMPs) 7 and 26 in ameloblastomas and adenomatoid odontogenic tumors (AOTs). STUDY DESIGN: Twenty intraosseous solid ameloblastomas and 10 intraosseous AOTs were evaluated regarding immunohistochemical expression of MMP-7 and -26 in the epithelium and stroma. RESULTS: There was no statistically significant difference in MMP-7 and -26 expression between the epithelium of ameloblastomas (P = .50) and AOTs (P = .90). Stromal staining for MMP-7 was evident in all cases. For MMP-26, stromal staining was observed in 65% of ameloblastomas and 50% of AOTs, and this difference was not statistically significant (P = .69). CONCLUSION: The marked expression of these matrilysins suggests their role in the process of tissue remodeling and growth in the studied tumors, but it does not relate to the their distinct patterns of aggressiveness.

Differential regulation of MMP-13 expression in two models of experimentally induced periodontal disease in rats.

OBJECTIVE: Evaluate expression of MMP-13 during the course of two models experimentally induced periodontal disease in rats. DESIGN: Expression of MMP-13 at mRNA and protein levels was studied, respectively, by reverse transcription polymerase chain reaction (RT-PCR) and Western blotting. Two experimental models were used: LPS injections and ligature placement. 30mug of LPS from Eschericia coli was injected twice a week into the palatal aspect of upper molars. Ligatures were placed at the gingival margin around lower first molars. Controls received injections of PBS vehicle and no ligatures on lower molars. Samples were collected 5, 15 and 30 days after initiation of periodontal disease and processed for extraction of total RNA, total protein, and routinely processed for histology. RESULTS: Both experimental models produced a significant increase on the inflammatory infiltrate that paralleled elevated levels of MMP-13 mRNA and protein at 5 and 15 days. The LPS model was associated with a sustained level of inflammation and increased MMP-13 mRNA throughout the 30 days, whereas the ligature model showed a decrease on the severity of inflammation and MMP-13 mRNA at the 30-day period. Interestingly, MMP-13 protein levels were diametrically contrary to the mRNA levels. CONCLUSION: MMP-13 expression during LPS- and ligature-induced experimental periodontal disease follows the increase on severity of inflammation at the earliest periods. At 30 days, there is a decrease on the severity of inflammation on the ligature model associated with decreased MMP-13 mRNA. There is a lack of transcription-translation coupling of MMP-13 gene in both experimental models.

Expression analysis of matrix metalloproteinase-9 in epithelialized and nonepithelialized apical periodontitis lesions.

OBJECTIVE: The objective of this study was to determine the expression of matrix metalloproteinase-9 (MMP-9) in apical periodontitis lesions. STUDY DESIGN: Nineteen epithelialized and 18 nonepithelialized apical periodontitis lesions were collected after periapical surgery. After histological processing, serial sectioning, H&E staining, and microscopic analysis, 10 epithelialized and 10 nonepithelialized lesions were selected for immunohistochemical analysis for MMP-9 and CD 68. At least one third of each specimen collected was frozen at -70 degrees C for further mRNA isolation and reverse transcription into cDNA for real-time-PCR procedures. Geometric averaging of multiple housekeeping genes normalized MMP-9 mRNA expression level. RESULTS: Polymorphonuclear neutrophils, macrophages and lymphocytes presented MMP-9 positive immunostaining in both types of lesions. When present, epithelial cells were also stained. The number and the ratio of MMP-9(+)/total cells were greater in nonepithelialized than epithelialized lesions (P = .0001) presenting a positive correlation to CD68(+)/total cells (P = .045). Both types of lesions presented increased MMP-9 expression (P < .0001) when compared to healthy periapical ligaments. However, no significant differences were observed for MMP-9 mRNA expression between ephithelized and nonephithelized lesions. CONCLUSION: The present data suggest the participation of several inflammatory cells, mainly CD68(+) cells, in the MMP-9 expression in apical periodontitis lesions. MMP-9 could be actively enrolled in the extracellular matrix degradation in apical periodontitis lesions.

Localized matrix metalloproteinase (MMP)-2 and MMP-9 activity in the rat ventral prostate during the first week of postnatal development.

The initial events in prostatic morphogenesis involve cell proliferation, epithelial canalization and outgrowth toward the stroma. We have hypothesized that stromal rearrangement takes place at the sites of epithelial growth and branching and that this rearrangement involves the action of gelatinases matrix metalloproteinase (MMP)-2 and MMP-9. Thus, the purpose of the present study was to characterize structural aspects of epithelial growth during the first week of postnatal development of the rat ventral prostate and to investigate the expression, localization and activity of MMP-2 and MMP-9 during this period by histological, ultrastructural and immunocytochemical analysis, in addition to gel zymography, in situ zymography and Western blotting. An increasing complexity of prostatic architecture was observed within the first postnatal week. Concurrently, the stroma became more organized and some cells differentiated into smooth muscle cells. Reticulin fibers appeared in a basket-like arrangement around both growing tips and epithelial sprouts, associated with a fainter staining for laminin. MMP-2 and MMP-9 activities were detected. MMP-2/MMP-9 expression decreased during the first week. Developing epithelial cords showed strong and difuse gelatinolytic activity. This activity coincided with the distribution of MMP-2 as determined by immunocytochemistry. On the other hand, MMP-9 was rather concentrated at the epithelial tips. These results suggest that gelatinolytic activity (with contribution of both MMP-2 and MMP-9) in the epithelium and at the epithelium-stroma interface are at least in part responsible for the tissue remodeling that allows epithelial growth and its projection into the surrounding stroma.

Toxicity of hexachlorobenzene and its transference from microalgae (Chlorella kessleri) to crabs (Chasmagnathus granulatus).

The aim of this work was to study the transference of hexachlorobenzene from a green alga (Chlorella kessleri) to an estuary crab (Chasmagnathus granulatus), and to analyze the toxic effects that the xenobiotic has on the latter. The effect of hexachlorobenzene uptake was evaluated measuring oxidative stress, Uroporphyrinogen decarboxylase activity and morphometric parameter alteration, and also performing a histological analysis of crab hepatopancreas. Results demonstrated that hexachlorobenzene enters the alga, is accumulated in it, and then transferred into the crab, causing a decrease in Uroporphyrinogen decarboxylase activity in both organisms. The high malondialdehyde levels detected in crab hepatopancreas after the toxic treatment suggested the existence of hexachlorobenzene-induced lipid peroxidation. Antioxidant defenses such as superoxide dismutase activity and reduced glutathione content fell below normal values on the fourth week of treatment. At the same time, the hepatosomatic index, used as a morphometric parameter, reduced 20% with respect to the control. The histological analysis revealed epithelium disorganization in hepatopancreas tubules, confirming the existence of structural damage caused by hexachlorobenzene.

17-beta-Estradiol upregulates COX-2 in the rat oviduct.

We investigated the regulation of cyclooxygenase-2 (COX-2) by 17-beta-estradiol (E2) in the rat oviduct. We observed that COX-2 is expressed mainly in proestrous and estrous stages, periods under estrogenic influence. While exogenous administration of E2 (1 microg/rat) significantly increased COX-2 protein levels, progesterone did not modify it. COX-2 was mainly localized on oviductal epithelial cells from estrogenized rat. Induction of COX-2 expression by E2 was partially reverted by tamoxifen (1 mg/rat), an E2 receptor antagonist. Estradiol treatment also increased prostaglandins (PGs) synthesis: 6-keto-PGF(1alpha) (40%), a stable metabolite of prostacyclin (PGI2), PGF(2alpha) (40%) and PGE2 (50%). Tamoxifen completely suppressed this enhancement. In order to discriminate which isoform of COX was implicated in the stimulatory effect of E2 on PGs synthesis, oviducts were preincubated with meloxicam (Melo: 10(-9)M) or NS-398 (10(-7)M), two selective COX-2 inhibitors. Both Melo and NS-398 abolished the increase of PGs synthesis stimulated by E2. All together, these data indicate that E2 could upregulate COX-2 expression and activity in the rat oviduct and that the stimulatory effect of E2 may be receptor-mediated.

Cyclooxygenase-2 expression in the endometrium and its relationship to bleeding in users of continuous oral contraceptives.

OBJECTIVE: The objective of the present study was to investigate whether or not the presence of irregular bleeding during use of oral contraceptives (OC) is associated with increased cyclooxygenase-2 (COX-2) expression. PATIENTS AND METHODS: An observational study was carried out in 26 patients who were using gestodene 75 microg/ethinylestradiol 30 microg prior to endometrial resection. The patients were divided into two groups: those with amenorrhea (n = 14) and those who had irregular bleeding (n = 12). The resected endometrium was immunostained for COX-2, Bcl-2 and Ki-67 expression. Routine pathology was carried out using standard hematoxylin-eosin staining. RESULTS: Irregular bleeding during OC use was associated with strong COX-2 expression in both glandular and superficial epithelium. There were also more patients in this group with irregular endometrial maturation and higher Ki-67 values. Bcl-2 expression, on the other hand, was not affected by the presence of uterine bleeding. CONCLUSION: The presence of irregular bleeding during OC use is associated with strong COX-2 expression in the endometrium, thereby suggesting a pivotal role of prostaglandins in this process.

Correlation of cyclooxygenase-2 and aromatase immunohistochemical expression in invasive ductal carcinoma, ductal carcinoma in situ, and adjacent normal epithelium.

The purpose of our study was to evaluate the correlation between cyclooxygenase-2 (COX-2) and aromatase immunohistochemical expression in ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC) present in the same breast, as well as in adjacent stroma and normal epithelium, we still correlated with nuclear grade, histologic grade, presence or absence of comedonecrosis, tumor size, and age at diagnosis. Forty-seven cases were evaluated through the use of anti-aromatase and anti-COX-2 polyclonal antibodies. Making the correlation of COX-2 and aromatase expression, we observed that COX-2 expression in IDC was correlated with aromatase expression in IDC (p < 0.001), DCIS (p < 0.001), normal epithelium (p = 0.024), and stroma tumor (p < 0.001). When the correlation was made between COX-2 expression in DCIS with aromatase, we observed positive correlation in IDC (p < 0.001), DCIS (p < 0.001), normal epithelium (p = 0.013), and stroma tumor (p < 0.001). In the correlative analysis of COX-2 expression in normal epithelium with aromatase in different evaluated tissues, we observed the following statistical results: IDC (p < 0.001), DCIS (p < 0.001), normal epithelium (p = 0.005), and stroma tumor (p = 0.047). Our results demonstrate the high correlation between COX-2 and aromatase expression in IDC, DCIS and normal epithelium, showing the importance of these two enzymes in the induction, promotion and progression of breast cancer.

Effect of the menstrual cycle and oral contraceptives on cyclooxygenase-2 expression in the endometrium.

OBJECTIVE: To compare the expression of cyclooxygenase-2 (COX-2) and proliferation markers (Ki-67) in the endometrium of patients with ovulatory cycles with those in the endometrium of patients using oral contraceptives. PATIENTS AND METHODS: Endometrial biopsies from 104 premenopausal patients with regular ovulatory cycles (n=90) or using an oral contraceptive (n=14) were selected for this study. Using immunohistochemical methods, both COX-2 (Novocastra clone 4H12) and Ki-67 (Dako clone MIB-1) expression were determined in the endometrium during the various phases of the menstrual cycle or following the use of oral contraceptives. RESULTS: COX-2 expression in the glandular epithelium was maximal during menstruation, the late proliferative phase and the early luteal phase, and minimal during the late luteal phase. However, in the surface epithelium, COX-2 expression remained strongly positive throughout the luteal phase. Ki-67 positivity increased during the proliferative phase and diminished during the luteal phase in the glands. In contraceptive users, both Ki-67 and COX-2 expression in the endometrium was low. CONCLUSION: The increased expression of COX-2 during menstruation and at mid-cycle is eliminated by the continuous use of oral contraceptives. This may be the rationale for their therapeutic action in the treatment of dysmenorrhea and bleeding.